Circuit testing instrument



July 5, 1932. H, ONKEN CIRCUIT TESTING INSTRUMENT Filed Nov 25, 1928 for Patented July .5, '1932 UNITED STATES I HEINRICH ONKEN, 0F OLDENBURG, GERMANY CIRCUIT TESTING INSTRUMENT Application led November 23, 1928. Serial No. 321,297.

This invention relates to a current flow testing instrument for electric circuits and lines of that type comprising a magnet coil into which a spring-controlled shiftable con- 5 tact pin is pulled when the circuit is closed. Thev circuit closing is effected by a freely movable ball contact which, when the instrument is in the Vertical position, touches a contact pin. W'hen the ball contact does not touch the contact pin thecircuit in the instrument is interrupted.

According to the invention a contact bar arranged in the direction of the longitudinal axis of the instrument engages With-inden- 15 tations of the magnet coil the contact sleeve and the connection plug and is insulated at the front end from the contact pin and the stopper, by two sleeves of insulation material for instance porcelain.

vAnother feature of the invention is that an insulated contact pin projects into the contact sleeve the ball slipping oi the rounded top end of said contact pin, when .the instrument is in vertical position,' so that it is securely brought into touch with the contact pin and with the contact sleeve.

The invention may be realized in various manners. 4 Two embodiments of the invention are il-l lustrated by Way `of example in the accomparying drawing in which: i.

Fig. l is a longitudinal section showing the test-in g instrument.

Fig. 2 is a cross section on line II-II of 3l Fig. 1.

Fig. 3 shows in elevation a portion of the contact bar, the outer sleeve being removed.

Fig. 4 illustrates another manner of application of the testing instrument.

`The testing instrument consists of an insulating sleeve a inv which a -coil b, a contact sleeve d with contact .ball c. and a connection plugk ,e are arranged. The contact ball c is of carbon so that the contact points of the sleeve d andof the contact pin d1 projecting into this sleeve are little by little covered with coal-dust whereby a. secure contact is ensured. The elements b, d and e are prevented from rotating by a narrow 50 contact-bar g, engaging' with indentations f of these elements, the bent olf end L of this contact barl g being clamped between a coil disc?)1 and a sleeve le of lnsulation material for instance porcelain held` by the screwed on 4metal cap i. This metal cap z' has aper- 55 tures Z and a suspension eye m and it coversv 'the spark pole n formed by an angular bent p of the contact bar for circuit closing. The

contact screw 1 is mounted in the connection plug e of the Wire u, u1. The Wire u1 ends in a'plate u2 to which the contact sleeve d is connected by means of a spring v. The contact sleeve (l with the ball c is Well insulated by insulating discs c1, c2 one at each end. The contact pin d1, the rounded end of which projects into the contact sleeve, is connected v by the Wire d2 to the coil winding b1 the other end bg of which is connected to the inner inv sulation sleeve 3 in which the Contact pin p is shiftably mounted. A spring da between so coil b and insulating disc o2 serves to securely mount the elements c1, c2.

The sleeve a is closed at the upper end by a cap w secured by a screw w1. Between connection plug e and cap w an insulating disc 'wg-is inserted. On the cap w a clamping nipple m is screwed, which tightens wedge elements m1 for clamping the cable u, u1 and for securing the same against pull and distortion.l

As the head i is made of metal it is resistant against breaking. By the construction described all the elements of the testing instrument are securely fixed in the sleeve a aswell .in longitudinal direction asvagainst rotation 95 The operation is as follows:

lVhen-the cable u, which ends in two terminals u. a3 is connected to an electric line, by the shifting of contact pin a continual spark is produced when the instrument is held vertically, for instance by suspending it by means of hook y on a. garment, and further a loud knocking of the contact pin, which indicates that current is in the line. The circuit is securely closed by ball c touching thel Contact pin d1 and the contact sleeve Z as, the instrument being in vertical or slightly inclined position, the ball c slides along pin d and efq fects a secure connection between contact sleeve Z and contact pin d1. `When the instrument is hung up on the eye m the circuit is completely interrupted.

T he instrument of tlie form of construction shown in Fig. 4 includes an electric alarm bell. i" The contact pin g2 has an extension p1 projecting through an aperture of cap vll.

The instrument is suspendedon a board 2 so that pin pl is capable of acting as a clapper upon the bell body 3. When the instrument is connected to the line 4 of an electric alarm bell, for instance by plug Contact 5 pin p will be continually moved up and down :is long as the circuit 4 is closed by a ball contact (i, the pin p striking tlie bell body 3, so that an alarm is sounded. This type of device is useful to give an audible alarm in stead of a spark signal under some conditions.

l claim:

W) An electric signalling device including an insulating tubular body having a cap at one end, a plug disposed in said body beneath said cap, a terminal on the under face of said plug, a. conductor leading from said terminal through said plug and cap, a magnet coil in said body and spaced from said plug, a pair of spaced insulating disks fitted in said body at the ends of said coil, a tubular core for said coil supported by said disks and opening through the lower disk, a second pair of y spaced insulating disks fitted in said body to form a chamber between the plug and coil, a contact sleeve fitted axially of the body between the disks of the second pair, ya pin extending through the upper disk of the second pair and having' conductive connection with' said terminal, a contact pin carried by tlieupper disk of the iirst pair and extending through the lower disk of the second pair, a contact ball loosely mounted in the sleeve and engageable with the Contact pin, a conductive connection between the contact pin and one end of the coil, said coil having its other end connected to the core, an insulating sleeve ex- @s tending downwardly from the lower of the first pair of disks, a cap surrounding the insulating sleeve, said cap and sleeve having registering sight ports at their lower ends, a contact member extending downwardly from the upper end of the body to the lower end of the sleeve and terminatin in a contact terminal, and a contact pin o 4 magnetic material slidable into and out from said core, and a spring normally holding the second contact pin on said last terminal.

' HEINRICH ONKEN. 

